Clockwork Future
by LoverofBooks1219
Summary: When two Herondales collide, the death of a thousand ducks is ensured. A crossover story; all character's are the great Cassandra Clare's
1. Chapter 1

**London Institute, 1887**

Tessa stretched her arms as she woke up, all her aches and pains returning. Her nap on the couch had been peaceful—though she could make do without Will watching over her. "Will?" She said groggily, "Why in the world are you watching me sleep?"

" _To love or have loved, that is enough. Ask nothing further. There is no other pearl to be found in the dark folds of life._ Or, in your case, the dark fold of your blanket." He kissed her, and sat down on the ottoman in front of her.

"Enough of Victor Hugo, I'm sick of _Les Miserables._ " Will had begun a fondness for the book. They started to read it together, but it bored Tessa. Terribly.

"Tell me why you were watching me sleep!" She urged. She put her swollen feet on the floor of the drawing room (which they had converted into a "reading room", complete with books that they had purchased with their own money), pleased with the way the cold floor tickled her bare feet.

"Firstly, one can never have too much Victor Hugo," he said. Then, he handed Tessa a black hard bound notebook, with pages and pages of names scribbled in. "Secondly, I was waiting for you to finish your nap so that we can discus baby names." Will opened the book to the very last page for Tessa. "I shortened the list for you so you wouldn't have to hear all the terrible names."

"How long was I asleep?" Tessa asked. She had been taking naps more often now, still not used to having a living person inside of her. She had the classic pains; swollen feet, back pain, and decreased tolerance for annoyance. She didn't even have enough strength anymore to make witty comebacks for Will.

"You fell asleep at the table, immediately after lunch, so I carried you here. Now it's—" he looked at his watch "—6pm."

"And you wrote all these names in 6 hours?" She was dumbstruck—she was just going to wait to name the baby after it was born. Just as she did with James. "And where is James?"

James was eager for his new baby brother or sister—he always competed with Will for who got to touch Tessa's stomach. At just one-year-old, he never failed to make Will's or Tessa's day brighter and better. It was easy to see who he took after just by looking at him. Though his eyes were a bright gold, and his hair was the same ruffled, raven black as Will's. But unlike Will, James was shy, and enjoyed spending time with his parents rather than other children. There was one child, that James enjoyed spending time with, and that was Matthew Fairchild, Charlotte and Henry's son.

When he began to walk, he strode over to Will's and Tessa's shared bookcase in their room, picked out _Treasure Island_. From then on, Will, Tessa, and James read from whatever book James picked out until one out of the three of them fell asleep. James was the first to doze off, and once he was asleep, Will and Tessa would read a book together (they alternated who picks the book to read that night).

"I actually started that list last night," Will said. "James helped me for a while, but then I set him down for his nap." Tessa went back to read the page, but her slow thinking mind caught up with what Will had said a few seconds back.

"Did you say that you _carried_ me?" Tessa didn't look exactly how she was nine years ago, when she was 17, when all their time was spent trying to find ways to stop Mortmain. James was a small baby, premature by about one month. She didn't have as much trouble carrying James, unlike this baby, who had 2 more weeks until he or she was ready.

That meant her stomach was big.

BIG.

"It's not that hard, Tess, to put on a Strength rune," he said. He then wickedly smiled, and Tessa knew immediately what joke was going to come out of his mouth.

"Don't," Tessa warned. "Don't test me, Will. I may be pregnant, but I have enough strength and training to punch you in the face." He held his lips together tightly, with his hands covering his mouth. When Will had a joke in mind, he had to get it out, no matter how dirty or rude it was. Tessa sighed. "Fine, let it out."

"It's not that hard to put on a Strength rune, Tess," he repeated, smiling. "Or two or three." He started laughing to himself, and Tessa couldn't help herself.

She started laughing as well.

She went back to looking at the baby names, names such as _Owen, Stephan, Jonathon,_ and _Billy Bones._ The last one was definitely said by James, after finishing _Treasure Island_. The next page was all girl names, such as _Eliza, Jenny, Juliet,_ and _Lucie._

"Lucie?" Tessa questioned. "As in, Lucie Manette?" Tessa loved _A Tale of Two Cities,_ but she felt Lucie Manette wasn't a good role model to take after _._

"Well, perhaps it should be something more along the lines of Lucie Herondale, but yes, that is what I was thinking her name should be. Has a nice ring to it, doesn't it?" She had to agree, it did sound quite nicely. "While I put James down for a nap, I saw _A Tale of Two Cities_ , and I had to re-read it. When I first read it, I thought it was a silly book, about a girl having to choose between two men. After you came to the Institute, I read it again. I understood the tragedy of loving and sacrificing. I read it again, today, and realized: _Lucie._

"That's when I realized: I want out daughter to be just like Lucie Manette—kind, devoted, passionate. Just like you." he stood from the ottoman, taking a seat next to her. "But Lucie should also be a reminder. Lucien Manette was competent, and submissive, always a damsel in distress. Lucie Herondale will never stand down, never worry about choices, never be submissive. She will be herself, and make her own choices. She won't step aside and let others make her decisions for her." He shook his head. Tessa was sure that he had become lost in his words.

"Giving someone a name makes them strive to be their best selves—to be like the person you named them after. Take James, for example. Jem is kind, gentle, and loyal. He is a reminder that there _are_ people in this world who aren't selfish, aren't thinking only about themselves." Tessa looked in to the candlelight next to her, trying to douse her tears. She didn't want Will to see her cry, even if she wasn't ashamed of crying in front of him anymore. The water left her eyes, and she looked back at Will with clear eyes.

"Then it's settled. Her name will be Lucie." She said with a clear voice, even though it felt like she had a swallowed an apple whole. "What if it's a boy?"

"Billy Bones seems like a nice name doesn't it? Billy Bones Herondale." She laughed, which she knew Will was trying to do.

She immediately frowned, feeling unsettled, feeling— _wrong_. Looking behind Will, she felt a strange energy, as if the room was going to suck all the room into itself. Gasping, she clutched her belly.

"Tess! Are you alright?" Will panicked. "Is it the baby?"

She shook her head, _no_. She didn't feel pain, just immense discomfort, as if she was stuck in a tank, and water was filling into it, slowly coming to the top. "Some—something is coming in," she attempted to say. She pointed behind Will, "come—coming, over—there." Will got up, and retrieved a seraph blade from underneath the couch. If this were a different situation, she would've scolded Will for hiding weapons in the reading room.

Will grabbed a stele from his pocket, drawing all the runes for going in to battle. Just as he finished, Tessa's discomfort subsided.

And the portal opened.

All of Tessa's and Will's books, the desk, chairs, James' play toys—they were all blown with a gust of wind. From the portal, two humans—Nephilim—emerged.

The female, had bright, flaming hair, and gem-like green eyes. She was short, and only reached until the other Shadowhunter's chest. The male, however, had blond hair and gold eyes like James. Tess felt like she had seen these people before. The curve of the girl's mouth, was exactly that of Henry's. The boy's, however, was much of that of Will's.

Perhaps…no. The idea was too preposterous to be true. That kind of technology hadn't been built yet.

"Who are you?" Will demanded. He was obviously astonished by the clothing choices these people had made. Both of these Nephilim had no weapons on them—no gear either. The only reason Tessa knew they were Shadowhunter was of the runes on their skin. The boy was wearing a plain blue sweater, and black trousers that—that stuck to his leg? Tessa wasn't quite sure. The girl was wearing a shirt that said _Sea Vegetable Conspiracy,_ and shorts that were much too improper for today's time.

Tessa then realized.

They weren't from _today's time._ But how?

"Hi," the girl started. "I hope we didn't intrude on anything." She looked uncomfortable, as if she didn't know what to say next. She looked at the boy, and he sighed.

"This is Clary Fairchild," he said. Will dropped his seraph blade and looked at Tessa, a clearly astonished look on his face.

He stepped forward to Will, and held out his hand, smiling. "By the Angel," Will whispered.

Tessa was certain Will had figured out who this boy was by looking at his features—his cheekbones, the sarcastic crinkle of his smile, the shape of his eyes—and the star shaped mark on his shoulder, which the sweater didn't cover.

"My name is Jace Herondale, and I think you're my great-great-great grandfather," he said bluntly. Tessa stood up, wanting to meet one of her descendants. Will only stared at this boy—Jace, his name was—and whispered, _fy ddisgynyddion, fy ngwaed, fy nheulu_

Tessa had picked up enough Welsh to understand what he said. _My descendant, my blood, my family._

"Was that Welsh?" he asked. Tessa didn't hear an answer from Will. Perhaps he was going through shock.

But soon she heard a thud.

Looking over, she saw that Will had fainted.


	2. Chapter 2

**London Institute, 1887**

When Will imagined having grandchildren, he had thought he would be 50 years old, approximately. He would have six grandchildren all around him, asking stories and being read to them. He thought he would take his whole family to Wales one day, lying on a hill and gazing at the crystal clear water, climbing Cadair Idris. He never would've imagined meeting his great-great-great grandson.

Much less meeting his great-great-great grandson who was the close to the same age as him.

When Will awoke, he had his family surrounding him. Tessa held a cool towel to his forehead, Clary next to her, and James was held by Jace. _What a sight,_ Will thought to himself. His wife and great-great-great granddaughter-in-law (or, he suspected that she was, from the way Jace looked at her) were chatting, and his son was being carried by his great-great-great grandson.

"Dada!" James yelled, smiling. Jace held out James so that Will could carry him.

"Jamie!" Will said, immediately getting up, resulting in the cold towel to fall down his face, and onto the floor. Once James had been handed to Will, Jace got up from his chair.

"I hope you're not going to faint again," Jace said, holding out his hand.

"As long as you do not call me or James 'grandfather', I will happily oblige." Will shook his hand, and Jace smiled. Tessa waddled over, with one hand on her stomach, looking as radiant as the sun, with Clary following. "Will!" She called.

 _Tess_. Whenever she called his name, he would close his eyes in pure bliss, and would want to hear it again. They had only been married 9 years, and for each year that passed his smile and heart grew more and more. He felt happy, whole, and…blessed, to say the least. Even that wasn't enough to describe how he felt since he married Tessa.

And once James came along, those feelings increased tenfold. He couldn't even imagine how happy he would be once his second child was born.

"Yes, Tess?" He said with a grin. Tessa stopped walking in front of him, Clary next to her.

"I was just finishing telling Clary about our story," Tessa said with bright eyes. He knew exactly which one. Their story.

His, Tessa's, and Jem's. "And what did she think of it?"

Her storm grey eyes, as usual, twinkled when she smiled. "She was very much surprised by how much we had endured. She was even more surprised when I told her the origins of her ginger hair."

"By the Angel, she has _got_ to meet Henry and Charlotte!"

Clary was giving Jace a summary of what Tessa told her, and Will could see Jace's eyes bulging out of his face. After Clary finished, Jace looked to Will. He was astonished, of what, Will had no clue.

"You two suffered a lot to get to where you are now," Jace said hoarsely. "I know what that feels like, not being able to be with the one person you want." _That's why he was astonished,_ Will thought. _He didn't think anyone else was like him._

"Oh, I can't wait any longer!" Tessa exclaimed. "These two claim they're from the New York Institute." Will frowned. How could these two leave the country, much less the state, dressed the way they are now?

"Isn't that run by"—

"In 2016."

Will's jaw dropped. _2016?_ It was only 1887! He knew he wouldn't live till then, but seeing that his bloodline was still there in the future gave him a great sense of pride. "How long are you here for?"

"We're here on a mission," Clary said. "But we didn't have enough time to learn how the mundanes act in this time period, so we came to an Institute. It was T—" Jace stopped her with a kiss, and when he pulled away, he gave her a look. Clary knew what Jace meant in that one look, and started a different discussion.

Will knew that bond. The kind where you could give one person a look, and they instantly knew what you meant. Will had that with two people. Tessa, and Jem.

"It was someone from our time who said we should come to the London Institute, and that you would welcome us." She said. "We can't reveal anything about the future. I don't know the science behind it, but Si—someone at the Institute explained it as, if we tell you something we're not supposed to, it could alter the choices you make, and change something in the future." She reached over towards Will and picked up James, who was fast asleep. "For example, if we told you something, that could alter the timeline in some way, and somehow causing Jace not to be born."

"And we can't let the world not see _this_ face at every waking moment," Jace said with a smirk. Will chuckled, knowing very well the extent of his arrogance and sarcasm—it was as if they had put a mirror in front of Will, changing the color of his hair and eyes.

"What _is_ this mission you lot are so secretive about?" Will asked. He looked to Clary, finally mustering up enough courage to ask them about their frivolous clothing. "And by the Angel, woman. Where are the rest of your clothes?" Clary and Jace laughed, while Tessa and Will looked to each other. It didn't particularly bother Will, what Clary was wearing, but it did make him uncomfortable. He didn't want to see another girl so...exposed, especially if that was her great-great-great granddaughter-in-law. But on Tess—

He would have to tell Tessa to borrow Clary's clothing sometime. For personal reasons.

"Why don't we move to the library and have tea? We can assist whatever mission you were sent on." Tessa waddled to the door, leading all of them. Will ran and caught up with Tessa, holding her hand.

"How did we get to be so lucky?" Will whispered. Tessa smiled, giving him a kiss on the cheek.

"We made our own luck, with help from a few others, of course."

After being a Wayland, Morgenstern, Lightwood, then finally a Herondale, Jace had enough with names. He didn't care what his last name was at that point; he just wanted a name to know where he came from, why he is who he is. But now, after 5 years of searching, he finally knew.

Will Herondale and Tessa Gray. _That_ was where he got all of his personality. His love of reading, hatred for ducks, his snarky and sarcastic attitude, the way he cares too deeply about everyone he gets close too—

Herondale. That was what he is, he knew, but now he knows what it means to be one. After hearing his great-great-great grandfather's tale, with the fake demon curse and lost parabatai, his heart ached for him in sympathy. He understood what if felt like, to be unable to be with the one you love, the one you want, the one person your heart aches for—

In his case, that person was Clary.

As his great-great-great grandparents led him and Clary to the library, Clary held his hand in hers and leaned against him. Against his ring finger, he felt a cold pang. He picked up her hand, her delicate, artist hands, and opened them. When he opened up her hand, he saw the ring he had got for her, promising marriage and a lifetime of happiness. "You wore it?" he asked. He couldn't believe; after all those times of asking and getting down on one knee, she finally wore it.

She sighed. "I couldn't resist. I really want to marry you, Jace, I'm just scared."

"Of what? The future? There'll always be problems, Clary, but—"

"Not _our_ future, Jace. Mine." She sighed again, as if she couldn't hold on to the burden anymore. "I have this nightmare, every night. It's me being trapped, and darkness—in short, it's me dying. I spoke to Magnus about it, and he says it might be a prediction of the future. I didn't want to marry you, only to leave you alone, to make you a widow." Jace let out a breath, a shaky one he didn't know he was holding. After a long silence, he finally found the words.

"I don't care."

Clary was startled, immediately locking eyes with him. "Excuse me?"

"I mean, I don't care that you would make me a widow. I might never find someone like you if you die, Clary, I might never love someone again. But that doesn't mean I'll be alone." They stopped at the end of a dim hallway, with witchlights illuminating their faces. "I have Alec, Izzy, Simon, Magnus—our whole family in New York. Being married to you, waking up next to you every day, saying that you're my wife, calling you 'Clary Herondale'—I want it all. I don't care if I'm only married to you for a day, or an hour. However long I'm married to you will be the happiest time of my life, because every single being of me loves you." As he looked in to Clary's eyes, he saw his answer. Clary jumped up, and wrapped her legs around Jace, kissing him, as if it were her last moment.

Kissing him, as if he was the only person in the world.

Jace decided then and there; Clary and he would live every day to the fullest.

As if it were their last.


	3. Chapter 3

Chapter 3

Before they had left, Magnus had repeatedly told them that Will Herondale looked like Alec, and to not be alarmed at the similarities.

When they got home, Jace made a mental note to tell Magnus that his memory was fading.

His great-great-great grandfather _did_ look a lot like Alec, that was correct—but his sister, the woman standing next to Will, had more similarities with Alec than Will did. Though Will and Alec shared the same eye color and hair color, Jace personally thought he looked more like Will than she did. His hair color and eye color were different, but their faces were almost identical when looking at each other.

Or maybe Jace just didn't want to share someone that was directly related to him.

As soon as the group of people walked into the massive library, Jace instinctively tightened his grip on Clary's hand, but then relaxed it, knowing that everyone at the London Institute was family. At least, that was what Magnus had told him, before he left.

"Time for introductions!" Will exclaimed, excitedly. "Clary, Jace, this is Henry Branwell-Fairchild, and standing next to him is Charlotte Fairchild. These are their sons, Charles and Matthew."

The young boy, Charles, —who Jace thought looked about nine or ten years old, considering he hadn't gotten any Marks yet—had red hair, matching his father, Henry, and Clary. Matthew was the same age as James, and were playing together in the corner. Jace wondered where he had heard the name _Branwell_ before, until he finally remembered.

"Henry Branwell, as in the creator of the Sensor?" Jace asked. Everyone in the group looked shocked, even Henry himself.

"How have you heard about my invention?" Henry asked him, his jaw dropping. "I only perfected it last night, and haven't even told my family, much less the Clave about it."

"Your sensors last for a long, long time. They're actually one of the tools we have to bring everywhere we go." Jace smiled at Henry, who was still staring at him in shock.

"Do you mean to tell me," Will interrupted, "that one of Henry's inventions is used in your time?"

Clary and Jace both nodded. Jace almost took out the Sensor that was in his backpack at that moment, but he didn't want to mess with the timeline. Who knows what would happen if Henry saw the modern advancements on the Sensor.

"Your sensor actually saved my life once." Clary smiled, a memory coming to both Jace's and her mind. "There was a Ravener demon, and I didn't have any weapons, so I threw my Sensor—well, technically, it was Jace's Sensor—and it killed the demon."

"That was my favorite Sensor," Jace added, "but that's besides the point."

Henry turned pale, his red hair looking like fire as he blanched in color. "May I ask, what time _are_ you people from?"

"2016." Jace said.

The entire group gasped, save for Will and Tessa. "2016?" the woman who looked like Alec exclaimed.

"Is that even a real year?" Charles asked Jace, his eyes wide.

"Of course it is," Jace said with a smile. "Just look at our clothes."

"Or your lack of them," Charlotte muttered. Jace laughed, surprising both himself and his extended family.

Will started to introduce people again. "Well, continuing on—this is Gabriel Lightwood and Cecily Heron—Lightwood." Will coughed, trying to hide his mistake. "This is my sister."

Cecily and Gabriel stepped forward. As they got closer, Jace realized that while Alec looked more like Cecily, Gabriel reminded him shockingly of Max—how Max would've looked if he had grown older, if he had not died in the Mortal War.

"You look so much like our time period's Lightwoods," Jace told them. Cecily and Gabriel looked at each other. Cecily pinched Will, shocking Jace. Did he say something wrong?

"Will! You haven't even introduced them to us yet. What are we supposed to say if we don't even know whose descendants we're talking to?"

"Calm down, woman. Your tricks on Gabriel will not work on me." He took a deep breath. "Okay, ladies and gentlemen, prepare yourselves. I present to you, Miss Clarissa Fairchild and Mr. Jace Herondale!"

Cecily nodded, taking the two of them in. Charlotte and Henry stared at each other, while Charles kept trying to ask his parents questions. Gabriel was wrapping his head around how many generations had passed between their time period and Jace's. Tessa and Will were watching this unfold, until Will stood up from the couch again.

"Oh, and I forgot to mention," Will said, after the excitement calmed down. "that these two here are engaged to be married. So that means, my dear Charlotte and Henry," Will took Henry and Charlotte's hand and shook it vigorously, "that we will be great-great-great grandparent's in laws!"

Everyone congratulated them, and then Henry finally began a conversation. "I'm glad my red hair has continued to generations to come," he said proudly.

Clary gave him a smile. "I had always wondered where my and my mother's red hair had come from."

"But how did you find out?" Jace asked and Tessa looked at each other, smiling.

"Well, when you're in the London Institute leading _certain_ guests to the library, you seem to realize that the guests stopped following you. And," Will added on to the end, "we overheard you two talking. You two weren't being very quiet about it."

Clary and Jace smiled, sheepishly.

"He's got the same eyes as James," Cecily noted. "And his facial structure is the same as yours, Will. I don't know who in the future has blond, but our father is blond, so that could be it." Cecily grabbed Will's hand and put him side by side to Jace. "You two are exact in height. What's your favorite book?" Cecily asked Jace. Jace shocked by the sudden series of questions, gave a slight hesitation before answering.

"Anything by Dickens, but I like poetry more than novels," Jace said. He went on. "And if you're trying to prove my Herondale-ness, go on ahead, great-great-great-great aunt Cecily," he said with a smirk.

Cecily smiled, and said, "Fine. I knew by the sarcasm that you were Will's heir."

"Another Herondale?" A young girl's voice rang throughout the room.

Jace turned around to hear who said that, looking around everywhere. He was sure he heard it, yet no one else noticed. Will whistled and smiled, as if he had heard it too. Will pointed to the sofa, where a young girl was sitting, her legs crossed.

"Is she a ghost?" Jace asked Will. He nodded.

"She used to live here, before she died in a battle at the Institute." Jace nodded, and waved to the girl. "Her name is Jessamine Lovelace," Will said.

 _Lovelace_ , Jace thought to himself. That was Simon's Shadowhunter last name.

"Herondale," she called out. Both Will and Jace turned their heads. "Not you, William, the younger, prettier one."

"Well, mind you Jessamine, there is no 'prettier' Herondale; each one is handsome in his own right." He laid a hand on Jace's shoulder, before leaving to be with his wife.

"Young Herondale," Jessamine said. "Tell me, honestly, are there any Lovelaces in your time? Any Lovelaces that are Shadowhunter?" Jace thought about his answer. He wondered if it would be an issue with the timeline if he told her, but Jace then realized—she was a ghost. No one else would pay attention to her.

"There was one—a mundane Lovelace. He tried to ascend, but…" Jace stopped there. Jessamine gave a sad smile.

"So my family has drifted apart from the Nephilim so much that they can't even Ascend."

"There is a new Lovelace, though." Jace said. Jessamine blinked.

"What, do you mean a baby? I guess you could train him or her and—,"

"No, I mean an active Shadowhunter named Simon Lovelace." Jessamine's eyes widened, and gave the tiniest smile. "He's not a Lovelace by blood—he was a mundane who was friends with the Lovelace that died. To honor him, Simon took the name Lovelace when he Ascended."

Jessamine gave a big smile. "Young Herondale—I mean, Jace—when you go back to your own time, take your fiancé, and this Simon Lovelace, and come to the London Institute. I'll still be here, and I want to meet this Simon."

"But he won't be able to see you," Jace said.

"No matter, I just want to see him."

Jace smiled, and said, "I promise. I'll come back."

**author's note: I'm not gonna lie, I completely forgot about writing and this story! I had writer's block, so I kinda put it off...for a good year? 2 years? Anyway, I can't promise when this is going to be updated, it could be tomorrow, next month, or in a year, but I will try to make it my best work! Thanks, and sorry again!


End file.
